Compressor capacity control operation mechanism and air conditioner provided with same

ABSTRACT

A compressor capacity control operation mechanism includes a pilot valve (flow channel switching valve) having capillary tubes, a suction branching pipe, an intermediate pipe, and a discharge branching pipe. The suction branching pipe is connected to a first capillary tube and branches off from a compressor suction pipe. The intermediate pipe is connected to a second capillary tube and a compressor cylinder intermediate part. The discharge branching pipe is connected to a third capillary tube and branches off from a compressor discharge pipe. Preferably, the suction, intermediate and discharge branching pipes have larger diameters than the first second and third capillary tubes. Also, the pilot valve preferably has a flow channel configuration switchable between first and second states in which the first, second and third capillary tubes are connected differently in the first and second states.

TECHNICAL FIELD

The present invention relates to a compressor capacity control operationmechanism and an air conditioner provided with the same; andparticularly relates to a compressor capacity control operationmechanism connected to a compressor and capable of controlling thecapacity of the compressor, and to an air conditioner provided with thismechanism.

BACKGROUND ART

Conventionally, there have been air conditioners including avapor-compression refrigerant circuit. Among air conditioners includingthis type of refrigerant circuit, there are those that use aconfiguration in which a compressor capacity control operation circuitis connected to a compressor, thereby making it possible to performcapacity control for switching the operating state of the compressorbetween a full load operation for bringing the discharge capacity to100% with respect to the suction capacity, and an unload operation forreducing the discharge capacity relative to the suction capacity. Thecompressor capacity control operation circuit has a bypass pipe forconnecting a cylinder intermediate part of the compressor and a suctionpipe of the compressor, an electromagnetic valve provided to the bypasspipe and functioning as a two-way valve, a pilot pipe for connecting thedischarge pipe of the compressor and the cylinder intermediate part ofthe compressor, and a capillary tube provided to the pilot pipe; whereinthe compressor can be controlled into the full load operation by closingthe electromagnetic valve, and the compressor can be controlled into theunload operation by opening the electromagnetic valve (for example, seePatent Document 1).

<Patent Document 1>

Japanese Laid-open Patent Application No. 9-72625

DISCLOSURE OF THE INVENTION

However, in the compressor capacity control operation circuit describedabove, since merely the capillary tube is provided to the pilot pipe,the refrigerant flowing from the discharge pipe into the bypass pipethrough the pilot pipe is added to the refrigerant flowing from thecylinder intermediate part into the suction pipe through the bypass pipeduring the unload operation, and a situation occurs in which some of therefrigerant discharged from the compressor is needlessly bypassed to thesuction pipe, which is a cause of an increase in power consumption inthe compressor during the unload operation.

To overcome this problem, an electromagnetic valve functioning as atwo-way valve is provided not only to the bypass pipe but to the pilotpipe as well, and the electromagnetic valve provided to the bypass pipeis opened and the electromagnetic valve provided to the pilot pipe isclosed during the unload operation, thereby making it possible to ensurethat refrigerant does not flow from the discharge pipe into the bypasspipe through the pilot pipe. However, in this case, the compressorcapacity control operation circuit requires two electromagnetic valvesfunctioning as two-way valves, and the cost increases.

An object of the present invention is to provide a compressor capacitycontrol operation mechanism and an air conditioner provided with thismechanism, wherein cost increases can be prevented and the capacity ofthe compressor can be controlled in the same manner as in a case ofusing two two-way valves.

A compressor capacity control operation mechanism according to a firstaspect of the present invention is a compressor capacity controloperation mechanism that is connected to a compressor and is capable ofcontrolling the capacity of the compressor, comprising a flow channelswitching valve, a suction branching pipe, an intermediate pipe, adischarge branching pipe, and a fixing member. The flow channelswitching valve has a valve main body, a first capillary tube, a secondcapillary tube, and a third capillary tube. The valve main body has thesame function as when two two-way valves are used to form a flow channelconfiguration capable of switching between a first state in which afirst flow channel and a second flow channel are connected and a thirdflow channel is not connected to either the first or second flowchannel, and a second state in which the second flow channel and thethird flow channel are connected and the first flow channel is notconnected to either the second or third flow channel. The firstcapillary tube constitutes the first flow channel and extends from thevalve main body. The second capillary constitutes the second flowchannel extends from the valve main body. A third capillary tubeconstitutes the third flow channel and extends from the valve main body.The suction branching pipe is a pipe that branches off from a suctionpipe of the compressor, is connected to the first capillary tube, andhas a larger diameter than the first capillary tube. The intermediatepipe is a pipe connected to a cylinder intermediate part of thecompressor, connected to the second capillary tube, and provided with alarger diameter than the second capillary tube. The discharge branchingpipe is a pipe that branches off from a discharge pipe of thecompressor, is connected to the third capillary tube, and has a largerdiameter than the third capillary tube. The fixing member fixes the flowchannel switching valve and at least one of the suction branching pipe,the intermediate pipe, and the discharge branching pipe.

Since the compressor capacity control operation mechanism is configuredusing a valve having the first, second, and third capillary tubesextending from the valve main body as the flow channel switching valve,strength is reduced in the portion of the first capillary tube connectedto the suction branching pipe, the portion of the second capillary tubeconnected to the intermediate pipe, and the portion of the thirdcapillary tube connected to the discharge branching pipe.

In view of this, in the compressor capacity control operation mechanism,excessive stress is prevented from acting on the first, second, andthird capillary tubes by fixing the flow channel switching valve and atleast one of the suction branching pipe, the intermediate pipe, and thedischarge branching pipe to the fixing member. Thus, a compressorcapacity control operation mechanism can be provided, whereby the costincrease resulting from the use of two two-way valves is prevented andthe same compressor capacity control is achieved as in the case of usingtwo two-way valves.

A compressor capacity control operation mechanism according to a secondaspect of the present invention is the compressor capacity controloperation mechanism according to the first aspect of the presentinvention, wherein among the suction branching pipe, the intermediatepipe, and the discharge branching pipe, one or those fixed to the fixingmember are fixed to the fixing member at the portions in proximity tothe corresponding capillary tubes.

In this compressor capacity control operation mechanism, since one orthose fixed to the fixing member among the suction branching pipe, theintermediate pipe, and the discharge branching pipe are fixed to thefixing member at the portions in proximity to the correspondingcapillary tubes, it is possible to reliably prevent positionalmisalignment and the like in proximity to the capillary tubes of thesuction branching pipe, the intermediate pipe, and the dischargebranching pipe. The stress applied to the first, second, and thirdcapillary tubes can thereby be reliably reduced.

A compressor capacity control operation mechanism according to a thirdaspect of the present invention is a compressor capacity controloperation mechanism connected to a compressor and capable of controllingthe capacity of the compressor, the compressor capacity controloperation mechanism comprising a pilot valve for use as a four-wayswitching valve having four connecting capillary tubes, a suctionbranching pipe, an intermediate pipe, and a discharge branching pipe.The suction branching pipe is connected to a first capillary tube as oneof the four connecting capillary tubes and is branched off from asuction pipe of the compressor. The intermediate pipe is connected to asecond capillary tube as one of the four connecting capillary tubes andis connected to a cylinder intermediate part of the compressor. Thedischarge branching pipe is connected to a third capillary tube as oneof the four connecting capillary tubes and is branched off from adischarge pipe of the compressor.

In this compressor capacity control operation mechanism, since the pilotvalve for use as a four-way switching valve is used instead of twotwo-way valves, it is possible to provide a compressor capacity controloperation mechanism whereby the cost increase resulting from the use oftwo two-way valves is prevented, and the same compressor capacitycontrol is achieved as in the case of using two two-way valves.

A compressor capacity control operation mechanism according to a fourthaspect of the present invention is the compressor capacity controloperation mechanism according to the third aspect of the presentinvention, wherein a fourth capillary tube as one of the four connectingcapillary tubes is closed off.

In this compressor capacity control operation mechanism, theconfiguration is simplified because the same flow channel configurationas one configured from two two-way valves can be achieved by a simpleprocess of closing off one of the four connecting capillary tubes of thepilot valve for use as a four-way switching valve.

An air conditioner according to a fifth aspect of the present inventioncomprises a vapor-compression main refrigerant circuit including thecompressor, a four-way switching valve, a first heat exchanger, anexpansion mechanism, and a second heat exchanger; and the compressorcapacity control operation mechanism according to the third or fourthaspect of the present invention; wherein the same valve as a pilot valvefor use as a four-way switching valve constituting the four-wayswitching valve is used as the pilot valve for use as a four-wayswitching valve.

In this air conditioner, components can be shared, thereby contributingto reducing the cost of the entire air conditioner, because the pilotvalve for use as a four-way switching valve used in the compressorcapacity control operation mechanism is the same pilot valve for use asa four-way switching valve constituting the four-way switching valveincluded in the main refrigerant circuit.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic configuration diagram of an air conditioner inwhich a compressor capacity control operation mechanism according to anembodiment of the present invention is used.

FIG. 2 is a perspective view showing the schematic internal structure ofan outdoor unit.

FIG. 3 is a schematic longitudinal cross-sectional view showing thestructure of part A in FIG. 1 (i.e., the structure of a compressor and acompressor capacity control operation circuit).

EXPLANATION OF THE REFERENCE SIGNS

-   -   1 Air conditioner    -   22 Compressor    -   23 Four-way switching valve    -   24 Outdoor heat exchanger (first heat exchanger)    -   25 Expansion valve (expansion mechanism)    -   41 Indoor heat exchanger (second heat exchanger)    -   28 Suction pipe    -   30 Discharge pipe    -   79 Cylinder intermediate part    -   87 Suction branching pipe    -   88 Intermediate pipe    -   89 Discharge branching pipe    -   90, 23 b Pilot valve (flow channel switching valve, pilot valve        for use as a four-way switching valve)    -   91, Valve main body    -   93 a First capillary tube    -   93 b Second capillary tube    -   93 c Third capillary tube    -   93 d Fourth capillary tube    -   98 Fixing member

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the compressor capacity control operation mechanismaccording to the present invention, and an air conditioner comprisingthis mechanism are described herein below with reference to thedrawings.

(1) Configuration of Air Conditioner Entire Configuration

FIG. 1 is a schematic configuration diagram of an air conditioner 1 inwhich a compressor capacity control operation mechanism according to anembodiment of the present invention is used. In the present embodiment,the air conditioner 1 is an apparatus used for cooling and heating aroom interior, and is a so-called separated type air conditionercomprising primarily an outdoor unit 2, an indoor unit 4, and a firstrefrigerant communication pipe 6 and a second refrigerant communicationpipe 7 connecting the outdoor unit 2 and the indoor unit 4.Specifically, in the present embodiment, the outdoor unit 2 and theindoor unit 4 are configured by being connected by the refrigerantcommunication pipes 6, 7 constructed on site, after the outdoor andindoor units are shipped to the site of installation and installed. Arefrigerant circuit 10 of the air conditioner 1 of the presentembodiment is configured by connecting the outdoor unit 2 and the indoorunit 4 via the refrigerant communication pipes 6, 7.

<Indoor Unit>

Next, the configuration of the indoor unit 4 will be described usingFIG. 1.

The indoor unit 4 is connected to the outdoor unit 2 via the firstrefrigerant communication pipe 6 and the second refrigerantcommunication pipe 7, and the indoor unit 4 constitutes a part of therefrigerant circuit 10. The indoor unit 4 primarily has an indoorrefrigerant circuit 10 b constituting the part of the refrigerantcircuit 10. The indoor refrigerant circuit 10 b primarily has an indoorheat exchanger 41 as a second heat exchanger.

In the present embodiment, the indoor heat exchanger 41 is a heatexchanger that functions as a refrigerant heater during cooling, and asa refrigerant cooler during heating. One end of the indoor heatexchanger 41 is connected to the second refrigerant communication pipe7, and the other end is connected to the first refrigerant communicationpipe 6.

In the present embodiment, the indoor unit 4 comprises an indoor fan 42for taking indoor air into the unit and supplying the air to the roominterior after heat exchange has been conducted, and the indoor unit 4is capable of conducting heat exchange between the indoor air and therefrigerant flowing through the indoor heat exchanger 41. The indoor fan42 is rotatably driven by an indoor fan motor 42 a.

The indoor unit 4 also comprises an indoor controller 43 for controllingthe operations of the components constituting the indoor unit 4. Theindoor controller 43 has a microcomputer, a memory and the like providedin order to control the indoor unit 4, and is designed so as to becapable of exchanging control signals and the like with an outdoorcontroller 37 (described hereinafter) of the outdoor unit 2.

<Outdoor Unit>

Next, the configuration of the outdoor unit 2 will be described usingFIGS. 1 through 3. FIG. 2 is a perspective view showing the internalstructure of the outdoor unit 2. FIG. 3 is a schematic longitudinalcross-sectional view showing the structure of part A in FIG. 1 (i.e.,the structure of a compressor 22 and a compressor capacity controloperation circuit 35).

The outdoor unit 2 is connected to the indoor unit 4 via the firstrefrigerant communication pipe 6 and the second refrigerantcommunication pipe 7, and the outdoor unit 2 constitutes an outdoorrefrigerant circuit 10 a as a part of the refrigerant circuit 10.

The outdoor unit 2 has a structure (a so-called trunk structure) inwhich the interior of a unit casing 51 shaped as substantiallyrectangular parallelepiped box is divided into an air blower chamber S1and a machinery chamber S2 by a vertically extending partitioning plate56, and the outdoor unit 2 primarily has the unit casing 51, outdoorrefrigerant circuit structural components (described hereinafter)constituting the outdoor refrigerant circuit 10 a, an outdoor fan 36,and an electrical component assembly (not shown in FIG. 2) whichfunctions as an outdoor controller 37 (see FIG. 1) for controlling theoperations of the components constituting the outdoor unit 2.

The unit casing 51 primarily has a bottom plate 52, a top plate 53(shown by chain double-dashed lines in FIG. 2), a front plate 54 (shownby chain double-dashed lines in FIG. 2), a side plate 55 (shown by chaindouble-dashed lines in FIG. 2), and a partitioning plate 56.

The bottom plate 52 is a horizontally-long substantially rectangularmetal plate-shaped member constituting the bottom surface portion of theunit casing 51. The peripheral edges of the bottom plate 52 are foldedupward. The outer surface of the bottom plate 52 is provided with twofixing arms 57 fixed to the on-site installation surface. The fixingarms 57 are metal plate-shaped members having substantially U shapes ina front view of the unit casing 51 and extending from the front of theunit casing 51 toward the rear.

The top plate 53 is a horizontally-long substantially rectangular metalplate-shaped member constituting the top surface portion of the outdoorunit 2.

The front plate 54 is primarily a metal plate-shaped member constitutingthe front surface portion and the front part of the right-side surfaceof the unit casing 51, and the bottom part of the front plate 54 isfixed to the bottom plate 52 by screws or the like. Formed in the frontplate 54 is a discharge port 54 a for blowing out air that has beentaken into the air blower chamber S1 through suction ports (not shown)formed in the back surface and left-side surface of the unit casing 51.

The side plate 55 is primarily a metal plate-shaped member constitutingthe rear part of the right-side surface and the right back surfaceportion of the unit casing 51, and the bottom part of the side plate 55is fixed to the bottom plate 52 by screws or the like.

The partitioning plate 56 is a metal plate-shaped member disposed on thebottom plate 52 and extending vertically, and is disposed so as topartition the internal space in the unit casing 51 into two left andright spaces (i.e., the air blower chamber S1 and the machinery chamberS2). The bottom part of the partitioning plate 56 is fixed to the bottomplate 52 by screws or the like.

Thus, the internal space of the unit casing 51 is divided into the airblower chamber S1 and the machinery chamber S2 by the partitioning plate56. More specifically, the air blower chamber S1 is a space enclosed bythe bottom plate 52, the top plate 53, the front plate 54, and thepartitioning plate 56; and the machinery chamber S2 is a space enclosedby the bottom plate 52, the top plate 53, the front plate 54, the sideplate 55, and the partitioning plate 56. An outdoor heat exchanger 24and the outdoor fan 36 are disposed in the air blower chamber S1, andthe compressor 22, a four-way switching valve 23, and other outdoorrefrigerant circuit structural components, as well as the electricalcomponent assembly (not shown) are disposed in the machinery chamber S2,as will be described hereinafter. In the unit casing 51, the interior ofthe machinery chamber S2 can be made visible by removing the portion ofthe front plate 54 that faces the machinery chamber S2.

The outdoor refrigerant circuit structural components constituting theoutdoor refrigerant circuit 10 a include primarily an accumulator 21,the compressor 22, the four-way switching valve 23, the outdoor heatexchanger 24 as a first heat exchanger, an expansion valve 25 (not shownin FIG. 2) as an expansion mechanism, a first stop valve 26, and asecond stop valve 27. The outdoor heat exchanger 24 is herein disposedin the air blower chamber S1, and the outdoor refrigerant circuitstructural components other than the outdoor heat exchanger 24 aredisposed in the machinery chamber S2.

The accumulator 21 is a container for temporarily retaining alow-pressure refrigerant circulating within the refrigerant circuit 10connected between the suction port of the compressor 22 and the four-wayswitching valve 23, and is disposed in the right rear corner of themachinery chamber S2 in the present embodiment (see FIG. 2). The outletof the accumulator 21 is connected to the suction port of the compressor22 by a first suction pipe 28, and the inlet of the accumulator 21 isconnected to the four-way switching valve 23 by a second suction pipe29.

The compressor 22 is a compressor having the function of taking in andcompressing low-pressure refrigerant and discharging the resultinghigh-pressure refrigerant, and is disposed in the substantial center ofthe machinery chamber S2 in a plan view (see FIG. 2) in the presentembodiment, in a state in which the space for accommodating theelectrical component assembly (not shown in FIG. 2) and the four-wayswitching valve 23 and other outdoor refrigerant circuit structuralcomponents is opened on the upper side. The discharge port of thecompressor 22 is connected to the four-way switching valve 23 by adischarge pipe 30. The internal structure of the compressor 22 will bedescribed hereinafter, as will be the compressor capacity controloperation circuit 35 (not shown in FIG. 2) as a compressor capacitycontrol operation mechanism connected to the compressor 22. Thecompressor capacity control operation circuit 35 and the componentsother than the compressor capacity control operation circuit 35 in therefrigerant circuit 10 are described separately below. In thisdescription, the components other than the compressor capacity controloperation circuit 35 in the refrigerant circuit 10 are referred to asthe main refrigerant circuit.

The four-way switching valve 23 is a valve for switching the directionof refrigerant flow when switching between cooling and heating; and thevalve is capable of connecting the discharge port of the compressor 22with the outdoor heat exchanger 24 and the accumulator 21 with thesecond stop valve 27 during cooling, and of connecting the dischargeport of the compressor 22 with the second stop valve 27 and theaccumulator 21 with the outdoor heat exchanger 24 during heating. Thefour-way switching valve 23 is connected to the outdoor heat exchanger24 by a first refrigerant pipe 31 (only partially shown in FIG. 2) andis connected to the second stop valve 27 by a fourth refrigerant pipe34. In the present embodiment, the four-way switching valve 23 has afour-way switching valve main component 23 a, and a pilot valve 23 b(not shown in FIG. 1) connected to the four-way switching valve maincomponent 23 a. The pilot valve 23 b is referred to as a pilot valve foruse as a four-way switching valve for operating the four-way switchingvalve main component 23 a when the aforementioned switch between coolingand heating is made, and the pilot valve 23 b is fixed to the four-wayswitching valve main component 23 a (see FIG. 2).

In the present embodiment, the outdoor heat exchanger 24 is a heatexchanger that functions as a refrigerant cooler using outdoor air as aheat source during cooling, and as a refrigerant heater using outdoorair as a heat source during heating. One end of the outdoor heatexchanger 24 is connected to the first refrigerant pipe 31 (onlypartially shown in FIG. 2) via a plurality of branching pipes 24 a (notshown in FIG. 2). The other end of the outdoor heat exchanger 24 isconnected to a second refrigerant pipe 32 via a plurality of branchingpipes 24 b (not shown in FIG. 2) and a flow distributor 24 c (not shownin FIG. 2). In the present embodiment, the outdoor heat exchanger 24 isa cross-fin type fin-and-tube heat exchanger configured from a heattransfer tube and numerous fins, and is disposed in the air blowerchamber S1. The outdoor heat exchanger 24 has an L shape in a plan view,and is disposed along the left side surface and back surface of the unitcasing 51. A tube plate 24 d is provided to the right end of the outdoorheat exchanger 24.

In the present embodiment, the expansion valve 25 (not shown in FIG. 2)is an electrical expansion valve capable of depressurizing thehigh-pressure refrigerant cooled in the outdoor heat exchanger 24 duringcooling before the refrigerant is fed to the indoor heat exchanger 41,and of depressurizing the high-pressure refrigerant cooled in the indoorheat exchanger 41 during heating before the refrigerant is fed to theoutdoor heat exchanger 24. One end of the expansion valve 25 isconnected to the second refrigerant pipe 32. The other end of theexpansion valve 25 is connected to the first stop valve 26 by a thirdrefrigerant pipe 33.

The first stop valve 26 is a valve provided to the connecting portionbetween the refrigerant pipe in the outdoor unit 2 (the thirdrefrigerant pipe 33 in the present embodiment) the first refrigerantcommunication pipe 6 (shown by chain double-dashed lines in FIG. 2). Thesecond stop valve 27 is a valve provided to the connecting portionbetween the refrigerant pipe in the outdoor unit 2 (the fourthrefrigerant pipe 34 in the present embodiment) connects with the secondrefrigerant communication pipe 7 (shown by chain double-dashed lines inFIG. 2). The second stop valve 27 is connected to the four-way switchingvalve 23 by the fourth refrigerant pipe 34.

The outdoor fan 36 is an air-blowing fan that functions so as to takeair into the air blower chamber S1 through suction ports (not shown)formed in the left side surface and back surface of the unit casing 51,and to blow the air from the discharge port 54 a formed in the frontsurface of the unit casing 51 after the air has passed through theoutdoor heat exchanger 24. In the present embodiment, the outdoor fan 36is a propeller fan and is disposed downstream of the outdoor heatexchanger 24 in the air blower chamber S1. The outdoor fan 36 isconfigured so as to be rotatably driven by an outdoor fan motor 36 a.

The electrical component assembly (not shown) is disposed in the upperspace of the machinery chamber S2, and the assembly has a control boardincluding a microcomputer or the like for performing operation control,an inverter board, and various other electrical components.

Next, the internal structure of the compressor 22 and the compressorcapacity control operation circuit 35 will be described in detail.

In the present embodiment, the compressor 22 is a hermetic compressor inwhich primarily a compression element 62, an Oldham ring 73, acompressor motor 75, and a bottom main bearing 76 are housed inside acasing 61, which is an upright cylindrical container.

The casing 61 primarily has a substantially cylindrical core plate 61 a,a top panel 61 b fixed by welding to the top end of the core plate 61 a,and a bottom panel 61 c fixed by welding to the bottom end of the coreplate 61 a.

The compression element 62 is a scroll-type compression elementprimarily having a housing 63, a fixed scroll 64 disposed above thehousing 63, and an orbiting scroll 65 that meshes with the fixed scroll64. The housing 63 is fixed by press-fitting into the core plate 61 a inthe external peripheral surface throughout the entire circumferentialdirection. The interior of the casing 61 is thereby partitioned into ahigh-pressure space S3 at the lower part of the housing 63 and alow-pressure space S4 at the upper part of the housing 63. A housingconcave part 63 a recessed in the center of the top surface and abearing part 63 b extending downward from the center of the bottomsurface are also formed in the housing 63. A bearing hole 63 cpenetrating through the bearing part 63 b in the vertical direction isformed therein, and a drive shaft 66 is rotatably fitted into thebearing hole 63 c via a bearing 67. The fixed scroll 64 primarily has apanel 64 a, a spiral (involute) wrap 64 b formed on the bottom surfaceof the panel 64 a, and a second external peripheral wall 64 c enclosingthe wrap 64 b. A discharge channel 69 communicated with a compressionchamber 68 (described hereinafter) and an expanding concave part 70communicated with the discharge channel 69 are formed in the panel 64 a.The discharge channel 69 is formed so as to extend vertically in themiddle portion of the panel 64 a. The expanding concave part 70 isconfigured from a horizontally expanding concave part that is recessedin the top surface of the panel 64 a. A lid 71 is fixed by a bolt 72 tothe top surface of the fixed scroll 64 so as to close off the expandingconcave part 70. By covering up the expanding concave part 70 with thelid 71, the expanding concave part 70 is partitioned from thelow-pressure space S4 (i.e., communicated with the high-pressure spaceS3), forming a muffler space S5 composed of an expansion chamber formuffling operation noises in the compression element 62. The orbitingscroll 65 primarily has a panel 65 a, a spiraling (involute) wrap 65 bformed on the top surface of the panel 65 a, a bearing part 65 c formedin the bottom surface of the panel 65 a, and a groove 65 d formed inboth ends of the panel 65 a. The orbiting scroll 65 is supported on thehousing 63 by fitting the Oldham ring 73 into the groove 65 d. The topend of the drive shaft 66 is also fitted into the bearing part 65 c. Theorbiting scroll 65 is thus incorporated into the compression element 62,whereby the orbiting scroll 65 revolves within the housing 63 withoutrotating on its axis due to the rotation of the drive shaft 66. The wrap65 b of the orbiting scroll 65 is meshed with the wrap 64 b of the fixedscroll 64, and the compression chamber 68 is formed between the contactparts of the wraps 64 b, 65 b. The compression chamber 68 is designed sothat the volume between the wraps 64 b, 65 b constricts toward thecenter along with the revolution of the orbiting scroll 65. Acommunication channel 74 is formed through the fixed scroll 64 and thehousing 63 in the compression element 62. The communication channel 74is formed so that a scroll-side channel 74 a formed in the fixed scroll64 and a housing-side channel 74 b formed in the housing 63 arecommunicated with each other. The top end of the communication channel74, i.e., the top end of the scroll-side channel 74 a, opens into theexpanding concave part 70; and the bottom end of the communicationchannel 74, i.e., the bottom end of the housing-side channel 74 b, opensinto the high-pressure space S3 from the bottom end surface of thehousing 63.

The Oldham ring 73 is a member for preventing rotational movement of theorbiting scroll 65 as described above, and is fitted into an Oldhamgroove (not shown) formed in the housing 63.

In the present embodiment, the compressor motor 75 is a motor whosefrequency can be controlled by an inverter control element or the likemounted on the electrical component assembly (not shown), and the motoris disposed below the compression element 62. The compressor motor 75primarily has an annular stator 75 a fixed to the internal wall surfaceof the casing 61, and a rotor 75 b rotatably housed at a slight gap (airgap channel) from the internal peripheral side of the stator 75 a. Acopper wire is wound around the stator 75 a, and coil ends are formedabove and below. The rotor 75 b is linked to the orbiting scroll 65 ofthe compression element 62 by the vertically extending drive shaft 66.

The bottom main bearing 76 is disposed in a bottom space below thecompressor motor 75. The bottom main bearing 76 is fixed to the coreplate 61 a, forms a bearing at the bottom end of the drive shaft 66, andsupports the drive shaft 66.

The top panel 61 b of the casing 61 is provided with a suction nozzle 77running vertically through the low-pressure space S4 and having aninternal end fitted into the fixed scroll 64 to form the suction port ofthe compressor 22. The core plate 61 a of the casing 61 is also providedwith a discharge nozzle 78 whose inside end opens into the high-pressurespace S3 to form the discharge port of the compressor 22.

Furthermore, the compressor capacity control operation circuit 35 isconnected to the compressor 22 of the present embodiment to allowcapacity to be controlled so that the operating state is switchedbetween a full load operation in which the discharge capacity is 100%with respect to the suction capacity, and an unload operation in whichthe discharge capacity is reduced with respect to the suction capacity.A cylinder intermediate part 79 is provided in order to implement thistype of capacity control. The cylinder intermediate part 79 primarilyhas an unload channel 80, a valve hole 81, a bypass channel 82, a valve83, a spring 84, the above-described lid 71, and an intermediate nozzle85.

The unload channel 80 is formed in the fixed scroll 64 so as to extendvertically, and the bottom end of the unload channel is communicatedwith the compression chamber 68.

The valve hole 81 is formed in the fixed scroll 64 so as to extendupward from the top end of the unload channel 80, and the top end of thevalve hole 81 is covered by the lid 71.

The bypass channel 82 is a channel for guiding the refrigerant from thecompression chamber 68 to the low-pressure space S4 during the unloadoperation by establishing communication between the low-pressure spaceS4 and the compression chamber 68 via the unload channel 80 and thevalve hole 81, thereby substantially delaying the start of compression.The bypass channel 82 is formed in the fixed scroll 64 so as to causethe valve holes 81 to communicate with the low-pressure space S4.

The valve 83 is disposed in the valve hole 81 in a state of being urgedupward by the spring 84, and is designed to be capable of movingvertically within the valve hole 81 due to the balance between theurging force of the spring 84 and the pressure in an operationalpressure chamber 86 formed above the valve 83. Therefore, the unloadchannel 80 and the bypass channel 82 become divided by the valve 83 whenthe valve 83 has moved downward (i.e., the pressure in the operationalpressure chamber 86 is greater than the urging force of the spring 84),and the unload channel 80 and the bypass channel 82 communicate witheach other when the valve 83 has moved upward (i.e., the pressure in theoperational pressure chamber 86 is less than the urging force of thespring 84).

The intermediate nozzle 85 is provided so as to pass vertically throughthe top panel 61 b of the casing 61, the low-pressure space S4, and thelid 71; and to be communicated with the operational pressure chamber 86of the valve hole 81. Thus, in the compressor 2, the valve 83 isoperated according to the pressure applied to the operational pressurechamber 86 through the intermediate nozzle 85, thereby forming acylinder intermediate part 79 capable of opening and closing the unloadchannel 80.

The compressor capacity control operation circuit 35 is connected to thecompressor 22 having this cylinder intermediate part 79, as describedabove. The compressor capacity control operation circuit 35 primarilyhas a suction branching pipe 87, an intermediate pipe 88, a dischargebranching pipe 89, and a pilot valve 90 as a flow-channel switchingvalve, and is disposed in the space between the compressor 22 and thefour-way switching valve 23 placed one above the other in the presentembodiment (not shown in FIG. 2).

The suction branching pipe 87 is a refrigerant pipe that branches offfrom the suction pipe 28 of the compressor 22, and is smaller indiameter than the suction pipe 28 in the present embodiment.

The intermediate pipe 88 is a refrigerant pipe connected to the cylinderintermediate part 79 of the compressor 22 (more specifically, theintermediate nozzle 85), and is substantially the same in diameter asthe intermediate nozzle 85 in the present embodiment.

The discharge branching pipe 89 is a refrigerant pipe that branches offfrom the discharge pipe 30 of the compressor 22, and is smaller indiameter than the discharge pipe 30 in the present embodiment.

In the present embodiment, the pilot valve 90 is a pilot valve for useas a four-way switching valve, primarily having a valve main body 91, anelectromagnetic coil 92, and four connecting capillary tubes 93 a, 93 b,93 c, 93 d. The valve main body 91 primarily has a valve case 94, avalve body 95, and a plunger 96. The valve case 94 is a substantiallycylindrical member having a hollow space in the interior, wherein fourports 94 a, 94 b, 94 c, 94 d communicated with the interior space areformed in the external periphery of the valve case 94, and an opening 94e through which the plunger 96 is reciprocatingly inserted is formed ina portion at one axial end. In the present embodiment, the second port94 b, the first port 94 a, and the fourth port 94 d are disposed atsubstantially equal intervals in the axial direction from a positionnear the opening 94 e, and the third port 94 c is disposed so as to facethe first port 94 a. The valve body 95 is disposed inside the valve case94 and is linked to the axially distal end of the portion of the plunger96 inserted into the valve case 94. In the present embodiment, the valvebody 95 has a bowl shape. Inserting the plunger 96 deep into the valvecase 94 causes the valve body 95 to move away from the opening 94 e,allowing the first port 94 a and the fourth port 94 d to communicatewith each other and also the second port 94 b and the third port 94 c tocommunicate with each other; and reducing the depth of the insertion ofthe plunger 96 in the valve case 94 causes the valve body 95 to movetoward the opening 94 e, allowing the first port 94 a and the secondport 94 b to communicate with each other and also the third port 94 cand the fourth port 94 d to communicate with each other. Theelectromagnetic coil 92 is disposed so as to enclose the externalperiphery of the portion of the plunger 96 protruding axially out of thevalve case 94. In the present embodiment, in the nonconductive state,the plunger 96 is inserted deep into the valve case 94, whereby thevalve body 95 moves away from the opening 94 e, the first port 94 a andthe fourth port 94 d are brought in communication with each other, andthe second port 94 b and the third port 94 c are brought incommunication with each other; and in the conductive state, the depth ofthe insertion of the plunger 96 into the valve case 94 is reduced,whereby the valve body 95 moves toward the opening 94 e, the first port94 a and the second port 94 b are brought in communication with eachother, and the third port 94 c and the fourth port 94 d are brought incommunication with each other. One end of the first capillary tube 93 ais connected to the first port 94 a, and the other end is connected tothe suction branching pipe 87, which is larger in diameter than thefirst capillary tube 93 a. One end of the second capillary tube 93 b isconnected to the second port 94 b, and the other end is connected to theintermediate pipe 88, which is larger in diameter than the secondcapillary tube 93 b. One end of the third capillary tube 93 c isconnected to the third port 94 c, and the other end is connected to thedischarge branching pipe 89, which is larger in diameter than the thirdcapillary tube 93 c. One end of the fourth capillary tube 93 d isconnected to the fourth port 94 d, and the other end is closed off.Thus, one of the four connecting capillary tubes, the fourth capillarytube 93 d, is closed off, whereby the valve main body 91 of the pilotvalve 90 has the same function as when two two-way valves are used toform a flow channel configuration in which the suction branching pipe 87and the first capillary tube 93 a communicated with the first port 94 aconstitute a first flow channel, the intermediate pipe 88 and the secondcapillary tube 93 b communicated with the second port 94 b constitute asecond flow channel, and the discharge branching pipe 89 and the thirdcapillary tube 93 c communicated with the third port 94 c constitute athird flow channel; in which case it is possible to switch between afirst state (corresponding to the conductive state of theelectromagnetic coil 92 in the present embodiment) in which the firstflow channel and the second flow channel are connected and the thirdflow channel is not connected to either the first or second flowchannel, and a second state (corresponding to the nonconductive state ofthe electromagnetic coil 92 in the present embodiment) in which thesecond flow channel and the third flow channel are connected and thefirst flow channel is not connected to either the second or third flowchannel. The state of the pilot valve 90 in FIG. 3 corresponds to a casein which the electromagnetic coil 92 is in the nonconductive state. Thesolid lines associated with the pilot valve 90 in FIG. 1 correspond to acase in which the electromagnetic coil 92 is in the nonconductive state,and the dashed lines associated with the pilot valve 90 in FIG. 1correspond to a case in which the electromagnetic coil 92 is in theconductive state.

When the full load operation is performed, the electromagnetic coil 92is in the nonconductive state, whereby the second port 94 b and thethird port 94 c of the pilot valve 90 are brought into communicationwith each other, and the first port 94 a is not communicated with eitherof the second or third ports 94 b, 94 c. The pressure of the cylinderintermediate part 79 in the operational pressure chamber 86 therebyincreases, and the unload channel 80 and the bypass channel 82 aredivided by the valve 83, therefore allowing compression work to beperformed without delaying the start of compression. When the unloadoperation is performed, the first port 94 a and the second port 94 b ofthe pilot valve 90 are brought into communication with each other, andthe third port 94 c is not communicated with either of the first orsecond ports 94 a, 94 b. The pressure of the cylinder intermediate part79 in the operational pressure chamber 86 thereby decreases, and theunload channel 80 and the bypass channel 82 are brought intocommunication with each other, the refrigerant is guided into thelow-pressure space S4 from the compression chamber 68, and compressionwork is therefore performed with a delay in the start of compression.

Thus, since the compressor capacity control operation circuit 35 of thepresent embodiment uses the pilot valve 90 for the four-way switchingvalve instead of two two-way valves, the cost increase from using twotwo-way valves can be prevented, and the same capacity control for thecompressor 22 can be achieved as in the case of using two two-wayvalves. Moreover, when the pilot valve 90 is given a flow channelconfiguration identical to a flow channel configuration composed of twotwo-way valves, this is achieved by a simple process of closing off one(the fourth capillary tube 93 d in the present embodiment) of the fourconnecting capillary tubes 93 a, 93 b, 93 c, 93 d, and the configurationis therefore simplified. In the present embodiment, the valve used asthe pilot valve 90 is the same as the pilot valve 23 b for use as afour-way switching valve constituting the four-way switching valve 23included in the main refrigerant circuit, and components can thereforebe shared, thereby contributing to reducing the cost of the entire airconditioner 1.

However, since the pilot valve 90 for use as a four-way switching valveis used as a flow channel switching valve in the compressor capacitycontrol operation circuit 35 of the present embodiment, a valve is usedin which the first, second, and third capillary tubes 93 a, 93 b, 93 cextend from the valve main body 91. Therefore, strength is reduced inthe portion of the first capillary tube 93 a connected with the suctionbranching pipe 87, in the portion of the second capillary tube 93 bconnected with the intermediate pipe 88, and in the portion of the thirdcapillary tube 93 c connected with the discharge branching pipe 89.

In view of this, in the compressor capacity control operation circuit 35of the present embodiment, the pilot valve 90 and at least one of thesuction branching pipe 87, the intermediate pipe 88, and the dischargebranching pipe 89 (the intermediate pipe 88 and the discharge branchingpipe 89 herein) are fixed to a fixing member 98, thereby ensuring thatexcessive stress does not act on the first, second, and third capillarytubes 93 a, 93 b, 93 c, and enabling the use of the pilot valve 90 foruse as a four-way switching valve. The fixing member 98 herein is asheet-shaped member made of sheet metal, and is disposed in the presentembodiment so as to at least face the connecting portion between thesecond capillary tube 93 b and the intermediate pipe 88 and theconnecting portion between the third capillary tube 93 c and thedischarge branching pipe 89. In the pilot valve 90, the electromagneticcoil 92 is fixed to the fixing member 98 by a band member 97 e. Theintermediate pipe 88 and the discharge branching pipe 89 are fixed tothe fixing member 98 by band members 97 b, 97 c, respectively. In thepresent embodiment, the pipes fixed to the fixing member 98 among thesuction branching pipe 87, the intermediate pipe 88, and the dischargebranching pipe 89 (the intermediate pipe 88 and the discharge branchingpipe 89 herein) are fixed to the fixing member 98 by the portionsthereof in proximity to the corresponding capillary tubes 93 b, 93 c.Therefore, positional misalignment or the like in the capillary tubeproximities of the suction branching pipe 87, the intermediate pipe 88,and the discharge branching pipe 89 can be reliably prevented, wherebystress acting on the first, second, and third capillary tubes 93 a, 93b, 93 c can be reliably reduced. In the present embodiment, theconnecting portion between the first capillary tube 93 a and the suctionbranching pipe 87 is not fixed to the fixing member 98, but at least oneof the suction branching pipe 87, the intermediate pipe 88, and thedischarge branching pipe 89 is preferably fixed to the fixing member 98.For example, the suction branching pipe 87 may be fixed to the fixingmember 98 by a band member similar to the intermediate pipe 88 and thedischarge branching pipe 89, or any one of the suction branching pipe87, the intermediate pipe 88, and the discharge branching pipe 89 may befixed to the fixing member 98.

The outdoor controller 37 has a microcomputer, a memory and the likeprovided in order to control the outdoor unit 2, and the outdoorcontroller 37 is designed to be capable of exchanging control signals orthe like with the indoor controller 43 of the indoor unit 4.Specifically, a controller as an operation control means for performingoperation control for the air conditioner 1 is configured by the indoorcontroller 43 and the outdoor controller 37.

The outdoor refrigerant circuit 10 a, the indoor refrigerant circuit 10b, and the refrigerant communication pipes 6, 7 are connected asdescribed above to form the refrigerant circuit 10 that is capable ofheating and cooling a room interior and that has the main refrigerantcircuit including the compressor 22, the four-way switching valve 23,the outdoor heat exchanger 24 as a first heat exchanger, the expansionvalve 25 as an expansion mechanism, and the indoor heat exchanger 41 asa second heat exchanger, and also has the compressor capacity controloperation circuit 35 connected to the compressor 22 and used to enablethe capacity of the compressor 22 to be controlled. The air conditioner1 of the present embodiment is designed to be capable of controlling thedevices of the outdoor unit 2 and the indoor unit 4 by a controllerconfigured from the indoor controller 43 and the outdoor controller 37.

(2) Operation of Air Conditioner Operation During Full Load Operation

First, the operation during cooling will be described using FIGS. 1 and3.

During cooling, the four-way switching valve 23 is in the state shown bythe solid lines in FIG. 1; i.e., a state in which the discharge side ofthe compressor 22 is connected to the outdoor heat exchanger 24 and thesuction side of the compressor 22 is connected to the second stop valve27. The degree of opening of the expansion valve 25 is adjustable. Thestop valves 26, 27 are in an open state. Furthermore, theelectromagnetic coil 92 of the pilot valve 90 is in the nonconductivestate.

When the compressor 22, the outdoor fan 36, and the indoor fan 42 arestarted up while the refrigerant circuit 10 is in this state, thelow-pressure refrigerant is taken in by the compressor 22 and compressedto be a high-pressure refrigerant. Since the electromagnetic coil 92 ofthe pilot valve 90 is in the nonconductive state herein, the result is astate in which the second port 94 b and the third port 94 c of the pilotvalve 90 are brought into communication with each other, and the firstport 94 a is not communicated with either of the second or third ports94 b, 94 c, whereby compression work is performed in the compressor 22without delaying the start of compression, and a full load operation isperformed in which the discharge capacity is 100% with respect to thesuction capacity. The high-pressure refrigerant is then fed via thefour-way switching valve 23 to the outdoor heat exchanger 24 functioningas a refrigerant cooler, heat exchange is conducted between therefrigerant and outdoor air supplied by the outdoor fan 36, and therefrigerant is cooled. The high-pressure refrigerant cooled in theoutdoor heat exchanger 24 is depressurized by the expansion valve 25 tobe a low-pressure gas-liquid two-phase refrigerant, which is fed via thefirst stop valve 26 and the first refrigerant communication pipe 6 tothe indoor unit 4. The low-pressure gas-liquid two-phase refrigerant fedto the indoor unit 4 is heated through heat exchange with indoor air inthe indoor heat exchanger 41 functioning as a refrigerant heater, andthe refrigerant is thereby evaporated to be a low-pressure refrigerant.The low-pressure refrigerant heated in the indoor heat exchanger 41 isthen fed via the second refrigerant communication pipe 7 to the outdoorunit 2, and is again taken in by the compressor 22 via the second stopvalve 27, the four-way switching valve 23, and the accumulator 21. Thus,cooling is performed. The capacity of the compressor 22 during the fullload operation is controlled primarily by frequency control of thecompressor motor 75.

Next, the operation during heating will be described using FIGS. 1 and3.

During heating, the four-way switching valve 23 is in the state shown bythe dashed lines in FIG. 1; i.e., a state in which the discharge side ofthe compressor 22 is connected to the second stop valve 27, and thesuction side of the compressor 22 is connected to the outdoor heatexchanger 24. The degree of opening of the expansion valve 25 isadjustable. The stop valves 26, 27 are in an open state. Furthermore,the electromagnetic coil 92 of the pilot valve 90 is in thenonconductive state.

When the compressor 22, the outdoor fan 36, and the indoor fan 42 arestarted up while the refrigerant circuit 10 is in this state, thelow-pressure refrigerant is taken in by the compressor 22 and compressedto be a high-pressure refrigerant. Since the electromagnetic coil 92 ofthe pilot valve 90 is in the nonconductive state herein, the result is astate in which the second port 94 b and the third port 94 c of the pilotvalve 90 are brought into communication with each other and the firstport 94 a is not communicated with either of the second or third ports94 b, 94 c, whereby compression work is performed in the compressor 22without delaying the start of compression, and a full load operation isperformed in which the discharge capacity is 100% with respect to thesuction capacity. The high-pressure refrigerant is then fed via thefour-way switching valve 23, the second stop valve 27, and the secondrefrigerant communication pipe 7 to the indoor unit 4. The high-pressurerefrigerant fed to the indoor unit 4 is then cooled through heatexchange with indoor air in the indoor heat exchanger 41 functioning asa refrigerant cooler, and the refrigerant is then fed via the firstrefrigerant communication pipe 6 to the outdoor unit 2. Thehigh-pressure refrigerant fed to the outdoor unit 2 is depressurized bythe expansion valve 25 to be a low-pressure gas-liquid two-phaserefrigerant, and then flows into the outdoor heat exchanger 24functioning as a refrigerant heater. The low-pressure gas-liquidtwo-phase refrigerant that has flowed into the outdoor heat exchanger 24is heated through heat exchange with outdoor air supplied by the outdoorfan 36, the refrigerant is thereby evaporated to be a low-pressurerefrigerant, and the refrigerant is taken back into the compressor 22via the four-way switching valve 23 and the accumulator 21. Thus,heating is performed. The capacity of the compressor 22 during the fullload operation is controlled primarily by performing frequency controlof the compressor motor 75.

<Action During Unload Operation>

The full load operation as described above is performed in areas inwhich the operating efficiency of the refrigeration cycle iscomparatively favorable in cases in which the ratio of the pressure ofthe high-pressure refrigerant with respect to the pressure of thelow-pressure refrigerant in the refrigeration cycle is suppressed at apredetermined range or lower, or in cases in which the frequency of thecompressor motor 75 is in a comparatively high range. Therefore, thereare many cases in which controlling the frequency of the compressormotor 75 is sufficient to control the capacity of the compressor 22.

However, in cases in which the ratio of the pressure of thehigh-pressure refrigerant with respect to the pressure of thelow-pressure refrigerant in the refrigeration cycle exceeds thepredetermined range, or in cases in which the frequency of thecompressor motor 75 is in a low range, conditions arise in which thecapacity of the compressor 22 cannot be sufficiently controlled merelyby controlling the frequency of the compressor motor 75, or theoperation is performed in an area of poor operating efficiency.

In view of this, the electromagnetic coil 92 of the pilot valve 90 isswitched to the conductive state in such a case, creating a state inwhich the first port 94 a and the second port 94 b of the pilot valve 90are brought into communication with each other, and the third port 94 cis not communicated with either of the first or second ports 94 a, 94 b,thereby creating a state in which the unload channel 80 and the bypasschannel 82 are communicated with each other and the refrigerant isguided from the compression chamber 68 to the low-pressure space S4.Compression work is thereby performed in the compressor 22 in a state inwhich the start of compression is delayed, an unload operation isperformed in which the discharge capacity is reduced with respect to thesuction capacity, and an operation in the state in which the compressormotor 75 has a low frequency is avoided.

The operating efficiency can thereby be prevented as much as possiblefrom decreasing, even in cases in which the ratio of the pressure of thehigh-pressure refrigerant with respect to the pressure of thelow-pressure refrigerant in the refrigeration cycle exceeds thepredetermined range, or in cases in which the frequency of thecompressor motor 75 is in a low range. Moreover, the pilot valve 90 isdesigned so that there are no situations in which some of therefrigerant discharged from the compressor 22 is needlessly bypassed tothe suction pipe 28 from the discharge pipe 30, similar to a case ofusing two two-way valves, and increases in power consumption in thecompressor 22 during the unload operation can therefore be suppressed.Furthermore, when switching between the full load operation and theunload operation, unlike a case of using two two-way valves, the numberof electrical wires can be reduced and the control specifics can besimplified because it is only necessary to control just the pilot valve90.

(3) Other Embodiments

An embodiment of the present invention was described above withreference to the drawings, but the specific configuration is not limitedto this embodiment, and modifications can be made within a range thatdoes not deviate from the scope of the invention.

<A>

In the embodiment described above, the fourth capillary tube 93 d wasclosed off among the four connecting capillary tubes 93 a to 93 d of thepilot valve 90, but the present invention is not limited to this option,and any one of the four connecting capillary tubes 93 a to 93 d can becan be closed off. In this case, the capillary tubes connected to thesuction branching pipe 87, the intermediate pipe 88, and the dischargebranching pipe 89 are changed according to the closed off capillarytube, whereby the pilot valve 90 preferably has the same flow channelconfiguration as one configured from two two-way valves, similar to theembodiment described above.

<B>

In the embodiment described above, a scroll compressor was used as thecompressor 22, and the compressor motor 75 was disposed in thehigh-pressure space S3 filled with high-pressure refrigerant, but thepresent invention is not limited to this option, and a rotary compressoror another such compressor may be used, and the compressor motor 75 maybe disposed in a space filled with low-pressure refrigerant.

<C>

In the embodiment described above, the outdoor unit 2 had a design inwhich the interior of the unit casing 51 was divided by the partitioningplate 56 into the air blower chamber S1 and the machinery chamber S2 andthe air taken into the unit casing 51 was blown out from the frontsurface of the unit casing 51, but the present invention is not limitedto this option, and another type of outdoor unit may be used, such as anoutdoor unit having a design in which air taken into the unit casing isblown out from the top surface of the unit casing. In the embodimentdescribed above, the air conditioner 1 was a so-called paired andseparated type air conditioner in which one indoor unit 4 was connectedto one outdoor unit 2, but other types of air conditioner may also beused, such as a remote-condenser type air conditioner or a multi-typeair conditioner in which a plurality of indoor units are connected toone or more outdoor unit.

INDUSTRIAL APPLICABILITY

Utilizing the present invention makes it possible to provide acompressor capacity control operation mechanism and an air conditionercomprising the mechanism wherein cost increases can be prevented and thecapacity of the compressor can be controlled in the same manner as in acase of using two two-way valves.

1. A compressor capacity control operation mechanism configured to beconnected to a compressor and to control capacity of the compressor; thecompressor capacity control operation mechanism comprising: a flowchannel switching valve including a valve main body having a flowchannel configuration switchable between a first state in which a firstflow channel and a second flow channel are connected and a third flowchannel is not connected to either the first flow channel or the secondflow channel, and a second state in which the second flow channel andthe third flow channel are connected and the first flow channel is notconnected to either the second flow channel or the third flow channel;with a first capillary tube forming the first flow channel and extendingfrom the valve main body; a second capillary tube forming the secondflow channel and extending from the valve main body; and a thirdcapillary tube forming the third flow channel and extending from thevalve main body; a suction branching pipe branching off from a suctionpipe of the compressor and having a larger diameter than the firstcapillary tube, the suction branching pipe being connected to the firstcapillary tube; an intermediate pipe connected to a cylinderintermediate part of the compressor and having a larger diameter thanthe second capillary tube, the intermediate pipe being connected to thesecond capillary tube; a discharge branching pipe branching off from adischarge pipe of the compressor and having a larger diameter than thethird capillary tube, the discharge branching pipe being connected tothe third capillary tube; and a fixing member having the flow channelswitching valve fixed thereto, and at least one of the suction branchingpipe, the intermediate pipe, and the discharge branching pipe fixedthereto.
 2. The compressor capacity control operation mechanismaccording to claim 1, wherein the at least one of the suction branchingpipe, the intermediate pipe, and the discharge branching pipe fixed tothe fixing member being fixed to the fixing member in proximity to thecapillary tube connected thereto.
 3. A compressor capacity controloperation mechanism configured to control compressor capacity; thecompressor capacity control operation mechanism comprising: a firstpilot valve having four connecting capillary tubes connected thereto,the first pilot valve being operable as a first four-way switchingvalve; a suction branching pipe connected to a first capillary tube ofthe four connecting capillary tubes and branched off from a compressorsuction pipe; an intermediate pipe connected to a second capillary tubeof the four connecting capillary tubes and connected to a compressorcylinder intermediate part; and a discharge branching pipe connected toa third capillary tube of the four connecting capillary tubes andbranched off from a compressor discharge pipe.
 4. The compressorcapacity control operation mechanism according to claim 3, wherein afourth capillary tube of the four connecting capillary tubes is closedoff.
 5. An air conditioner including the compressor capacity controloperation mechanism according to claim 3, the air conditioner furthercomprising: a vapor-compression main refrigerant circuit including acompressor, a switching valve including a second pilot valve operable asa second four-way switching valve, a first heat exchanger, an expansionmechanism, and a second heat exchanger, with the first pilot valveoperable as the first four-way switching valve being identical to thesecond pilot valve operable as the second four-way switching valve. 6.An air conditioner including the compressor capacity control operationmechanism according to claim 4, the air conditioner further comprising:a vapor-compression main refrigerant circuit including a compressor, afour-way switching valve, a first heat exchanger, an expansionmechanism, and a second heat exchanger, with the first pilot valveoperable as the first four-way switching valve being identical to thesecond pilot valve operable as the second four-way switching valve. 7.The compressor capacity control operation mechanism according to claim3, further comprising a fixing member having the first pilot valve fixedthereto, and at least one of the suction branching pipe, theintermediate pipe, and the discharge branching pipe fixed thereto;wherein the first pilot valve includes a valve main body having a flowchannel configuration switchable between a first state in which thefirst and second capillary tubes are connected and the third capillarytube is not connected to either the first capillary tube or the secondcapillary tube, and a second state in which the second and thirdcapillary tubes are connected and the first capillary tube is notconnected to either the second capillary tube or the third capillarytube; the suction branching pipe has a larger diameter than the firstcapillary tube; the intermediate pipe has a larger diameter than thesecond capillary tube; the discharge branching pipe has a largerdiameter than the third capillary tube.
 8. The compressor capacitycontrol operation mechanism according to claim 7, wherein the at leastone of the suction branching pipe, the intermediate pipe, and thedischarge branching pipe fixed to the fixing member is fixed to thefixing member in proximity to the capillary tube connected thereto.